Published on Web 04/01/2009
Probing Hydrophobic Interactions Using Trajectories of Amphiphilic Molecules at a Hydrophobic/Water Interface Andrei Honciuc and Daniel K. Schwartz* Department of Chemical and Biological Engineering, UniVersity of Colorado, Boulder, Colorado 80309 Received January 30, 2009; E-mail:
[email protected] Abstract: Individual molecules of fluorophore-labeled alkanoic acids with various chain lengths, BODIPY-(CH2)n-COOH (abbreviated as fl-Cn), were observed to adsorb and move at the methylated fused silica-water interface as a function of temperature using total internal reflection fluorescence microscopy. The statistical analysis of squared-displacement distributions indicated that the molecular trajectories were consistent with a diffusive model involving two intertwined modes. The slower mode, typically responsible for
